Gas burner control



Patented Oct. 27, 1942 s PATENT OFFICE ass BURNER common Edward 3. Done,Shaker Heights, Ohio, assignor to The Bryant Heater Company, Cleveland,

Ohio, a corporation of Ohio Application July 2, 1940, Serial No. 343,611

Claim. (Cl- 158- 117.1)

This invention relates to improvements in gas burner controls, and to doprimarily with a methodand means'for providing automatic burnerignition] wherein one pilot maintains an 18- niting flame during or!periods of the burner only; while a second pilot operating during the onperiods of the burner only performs the usual functions of a safetypilot and serves also to reignite the flrst' pilot at the conclusion ofan on period.

I The two pilots therefore operate alternately and never simultaneouslyexcept for a slight overlap sumcient to pass igniting flame from onetothe other.

One oi the objects of the invention is the provision of a systemproviding flame'lgnition wherein the lighting pilot is extinguishedduring the on periods of the burner, this feature being especiallyimportant in lighters for small capacity or broiler burners whereby theeflective burner pattern may be aflected to a minimum extent by thelighting apparatus.

Another object is the elimination of waste, the lighting pilot flamebeing of little value during the operation of the burner.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, I have illustrated in the accompanyingdrawing, in which Figs. 1 and 2 are diagrammatic illustrations of aburner control embodying the invention, Fig. 1 showing the same in theburner on position, and Fig. 2 in the burner of! position.

In the drawing Ill represents a gas burner of conventional character fedby a gas line H in which there may be a shut-of! valve l2, ordinarilymaintained in the open position. A diaphragm valve I3 is interposed inthe line between the valve i2 and the burner, this valve comprising adiaphragm ll forming one side of a pressure chamber i5. When there isline pressure in the chamber the valve is closed, as in Fig. 2, becausethe area exposed to line pressure on the upper side of the diaphragm isgreater than that on the lower side. On the other hand when the pressureabove the diaphragm is atmospheric line pressure below the diaphragmraises it and opens the valve, this being a conventional construction.

it is a conductor which is continuously in communication with line H solong as the valve i 2 remains'open. I1 is a conductor which iscontinuously in communication with .pressure chamber l5. Conductor I1 isin constant communication with a branch ll leading to a lighting pilot20' leads to a control pilot 2|. Pilots i9 and 2| are close enoughtogether to enable either one to be ignited by a flame from the other,while pilot 2| at least is mounted in igniting relation withmain burnerl0. Between conductors 20 and 20 there is a valve of any desiredcharacter for controlling the flow of gas to pilot 2|. In some cases, asin that herein illustrated, this valve maybe an electric valve 22 whichmay be operated thermostatically, as where the burner is a furnaceburner controlled from the premises to be heated. In other cases thevalve 22 may be a manual valve, as forexample in the case 01' an oven orbroiler burner.

On a bracket 23 in which the pilot 2! is sup- Ported there is mountedone leg of a thermal element 2| of horseshoe shape, disclosed andclaimed in Hahn Patent 2,064,909, which is so disposed as to be heatedby flames emerging from holes 25 in the lower portion of the pilot 2|.The expansion of element 24 when heated causes the free leg thereof topress against a longitudinally slidable rod 28 that acts upon a ballvalve 21 working against a spring 28 that tends to hold the valve awayfrom its seat 29 which is located at the end of a conductor 30 that isin communication with a conductor it. When valve 2.! is open conductor30 is in free communication through a passage 3i with conductor l8 andthence with conductor ll, as well as with lighting pilot l9.

Diaphragm I4 is held down against its seat during oil. periods of theburner by line pressure in chamber l5, supplied through conductors I6and 30, open valve 21, passage II and conductors l8 and".

19. From conductor ii to branch conductor 20,

Means may be provided additionally for supplying pressure to chamber IIto close the diaphragm valve in the event that some condition in thesystem calls for the closing of the valve as a safety measure. Asillustrative of means for effecting this result I have shown a normallyclosed valve 32 which, when opened, provides communication betweenconductors I6 and I! and thus supplies the necessary gas pressure tochamber i5 for closing the diaphragm valve. The valve 32 may be openedwhen steam pressure in a steam heating system reaches a predeterminedheight, when the temperature in a flue reaches a predetermined height,when the temperature of water in a hot water system reaches apredetermined height, etc. When the valve 32 is open the diaphragm valvecannot open, or if it is already open it will thenimmediately close.Safety devices of this nature are well known in the art.

Fig. 2 of the drawing shows the apparatus in the normal or oiIcondition. Pressure is built up in pressure chamber I5 by gas flowingthrough conductors l6 and 30 and open valve 21 into conductors l8 andI1. Valve 21 also admits gas .to the lighting pilot l9, which isburning. Now if valve 22 is opened flow of gas to control pilot 2| isinitiated. This pilot is then ignited from pilot [9 and the flametravels down pilot 2| tothe holes 25, the flame from which plays uponthe horseshoe 24 and causes it to expand. This expansion moves rod 26longitudinally to close valve burner, a lighting pilot and a controlpilot ar- 21 against its seat 29, after which the pressure in chamber l5and in the conductors I1 and I8 dissipates itself through the lightingpilot l9.

ranged in interigniting relation, a valve for the main burner, meansenabling pressure in the gas line to close said valve, said means alsoproviding flow of gas to said lighting pilot, valve controlled means forfeeding gas to said control pilot, and

, means responsive to the flame from. said control Diaphragm valve I 3therefore opens and gas flows to the burner which is ignited by theflame from pilot 2 I.

When after a period of burner operation the valve 22 is closed, cuttingoff gas to the pilot 2|, thermal element 24 contracts and permits spring.28 to open valve 21, which lets gas into the conductors l8 and I1 andthence into the chamber 15, resulting in the closing of the diaphragmvalve l3. Pilot I9 is then relighted by the lime from the residual gasin pilot 2| and conductor after which the latter pilot goes out.

Having thus described my invention, I claim:

1. In apparatus of the class described, a gas supply, a main burner, amain valve adapted to be closed by gas pressure, a lighting pilot and acontrol pilot arranged in interigniting relation and in ignitingrelation with the main burner, means for maintaining gas fiow to saidlighting pilot during off periods of the main burner, means for feedinggas to the control pilot at the beginning of an ignition cycle, andmeans responsive to the control pilot for relieving the pressure on saidmain valve and cutting of! gas to the lighting pilot, whereby-the mainburner goes on and the lighting pilot goes off after the control pilotis lighted.

2. .In apparatus ofthe classv described, a main burner, a lighting pilotand a control pilot arrangedin interigniting relation and in ignitingrelation with the main burner, means for maintaining gas flow to saidlighting pilot during the off periods of the main burner, means forfeeding gas to the control pilot at the beginning of an ignition cycle,and means responsive to the control pilot for admitting gas to the mainburner filled with gas under line pressure to hold the pilot forrelieving the pressure at said valve to open the same and for cuttingoff the supply of gas to said lighting pilot.

4. In a gas'burner control system, a main burner, a valve therefor, alighting pilot and a control pilot arranged in interigniting relation,said control pilot beingarranged in igniting relation with said mainburner, said main burner valve having a pressure chamber adapted whenvalve closed,-said pressure chamber being normally in communication withthe gas line and with the said lighting pilot, means for feeding gasfrom the line to said control pilot, a valve for said last na'med means,and means responsive to the flame from said control pilot for exhaustinggas from said pressure chamber and said lighting pilot.

5. In mechanism of the character described, a main burner," a pressurei'ctuated main valve, a lighting pilot,*a control pilot, meansfunctioning during'th'e oft periods of the main burner to supply gas tothe lighting pilot, means for causing gas to flow to the control pilotat the beginning of a lighting cycle, thermal means functioning inresponse to the operation of the control pilot to relieve pressure onthe main valve for opening the same and at the same time to interruptthe flow of gas to the lighting pilot, whereupon the main burner goes onand the lighting-pilot goes off, said thermal means functioning when thesupply of gas to the control pilot is. interrupted to again admit gas tothe lighting pilot and to applygas pressure to close the main valve.

EDWARD R. DOWNE.

